Consider not removing the failOnMissingSources option

[viniciusxyz]

I have a project that has 20 different modules, where 18 of them have protobuf files and 2 do not, in this case it becomes simpler to configure the plugin only in the parent pom instead of creating a pluginManagement and declaring the use of the plugin in each of the 18 modules, for this reason this configuration ends up simplifying the use of the plugin, removing it would force me to have to multiply the plugin declaration several times

[ascopes]

Noted... this sounds like a good argument for keeping it. Will raise into an issue and reinstate that functionality.

[viniciusxyz]

Thanks

[ascopes]

Moved discussion to #845.